Field of the Invention
The invention relates to a vacuum switching chamber having an approximately cylindrical switching chamber housing of insulating material, preferably of ceramic, a rod carrying a stationary contact piece engaging one axial end and a rod carrying a moving contact piece engaging another axial end of the housing, and a bellows being mounted on the switching chamber housing, being fastened to the switching chamber housing at one end and being fastened to and enclosing the rod for the moving contact piece at another end.
A vacuum switching chamber of the type mentioned above normally has a tubular body made of insulating ceramic with ends to which metallic terminating covers are fastened. The fastening is carried out by soldering, with the end surfaces of the tubular insulating body being metallized in advance. A stationary contact piece and a moving contact piece are provided in the interior of the switching chamber and are each fastened to a rod. The rods pass through the covers in a vacuum-tight manner and a metallic bellows, which allows the rod to move, is disposed between one of the covers and the rod of the moving contact piece.
Such a vacuum switching chamber has a relatively large structural volume. The different coefficients of expansion of metal and ceramic produce stresses which cannot be ignored, because of the large structural volume.